The structure of 16, 17β-epoxy-17α-pregn-5-en-3β-ol-20-one monohydrate

The structure of the title compound (1) has been studied by means of X-ray diffraction. The region of cycleD in epoxide1 was compared with that of the 16,17-epoxy derivatives of progesterone and pregnenolone (studied previously) as well as with that of the respective 16,17- and 16,17-cyclopropano analogs. In contrast to the 16,17-epoxy-20-oxo derivatives, in compound1 the electron conjugation of the epoxide ring with the CH₃CO group at C(17) is partly disrupted. Moreover, the steric congestion at C(17) is significantly less pronounced in 16,17-epoxide1 than in its 16,17-counterpart. Both of these factors, especially steric decongestion, are favorable for nucleophilic attack at C(17) in the molecule of1. The X-ray diffraction data do not contradict the previously advanced mechanism of epoxide ring opening in 16,17- and 16,17-epoxy-20-oxo steroids by nucleophilic reagents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 401–405, February, 1993.     

Simple Synthesis of 17α,20β-Dihydroxypregn-4-en-3-one

Reduction of 17-hydroxyprogesterone (1) with NaBH ₄ produces 17,20-dihydroxypregn-4-en-3-one (2) and pregn-4-en-3,17,20-triol (3)     

Reaction of Pregnenolone and 3α,5-Cyclo-5α-pregnan-6β-ol-20-one with Trifluoroperacetic Acid

The reaction of pregnenolone and 3,5-cyclo-5-pregnan-6-ol-20-one with trifluoroperacetic acid produces the trifluoroacetates, hydrolysis of which gives the 3,5alpha;,6-triol.     

Transformation of 5α-H-pregn-16-en-3β-ol-20-one into pregn-4-ene-9α,16α,17α-triol-3,20-dione 16,17-acetonide

A preparative method was proposed for the preparation of pregn-4-ene-9,16,17-triol-3,20-dione 16,17-acetonide (2) from 5-H-pregn-16-en-3-ol-20-one (1). The key stage in the proposed sequence of the reactions is the microbiological 9-hydroxylation and introduction of the 4-en-3-one grouping into the molecule of1 by R- and S-dissociative forms of the Rhodococcus sp. strain.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1898–1901, August, 1992.     

Novel Synthesis of 2β,3β,20β-Triacetoxy-5 -pregnan-6-one

Pregnenolone (2) is used in a novel synthesis of 2,3,20-triacetoxy-6-ketosteroid (6), a key intermediate in the preparation of 20-hydroxyecdysone (1)     

A Facile Synthesis of 4-(3β -Methoxy-5α-androstan-17β-YL)-3-pyrrolin-2-one

The title compound was prepared in 4 steps from 3β-methoxy-21-hydroxy-5α-pregnan-20-one (1). The required intermediate (4) was obtained using lithium enolate derived from t-butyl acetate. Interesting enough, p-tosyl chloride in pyridine quantitatively converted compound 1 into the α-chloro ketone derivative (2).     

Synthesis of 3β,6α-dihydroxy-5α-cholan-23-one

Evidence for the presence of 3β,6α-dihydroxy-5α-chol-9(11)-en-23-one in the aglycone mixture from the starfish Marthasterias glacialis is provided by the synthesis of 3β,6α-dihydroxy-5α-cholan-23-one (19) and its identification in the hydrogenated aglycone mixture. The side-chain is constructed from the 23,24-dinorcholanol (13) by reaction of the 22-tosylate (16) with the acetylide anion, followed by hydration of the resulting 23-yne (17).     

Synthesis of diglycosides of 3β,20S-dihydroxydammar-24-en-12-one

The 3-O-β-D-galactopyranosyl-20-O-β-D-glucopyranoside and 3-O-β-D-glucopyranosyl-20-O-β-Dgalactopyranoside of 3β,20S-dihydroxydammar-24-en-12-one, which are structural analogs of chikusetsusaponin-LT₈ (1), a minor glycoside from Panax japonicus, were synthesized for the first time.     

Synthesis of (24R)-3β-hydroxystigmast-5-en-7-one

The natural compound (24R)-3-hydroxystigmast-5-en-7-one has been synthesized from -sitosterol.Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus', 220141, Belarus', Minsk. Ul. Akad. Kuprevicha, 5/2. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 484–487, July–August, 1999.     

Synthesis and studies of some cholest-5-en-3-ol-(3β)[4-phenylpyridylazo]carbonate-containing supramolecular hydrogen-bonded mesogens

Mesogenic materials containing cholest-5-en-3-ol-(3β)[4-phenylpyridylazo]carbonate (CPPC) and 4-n-alkyloxybenzoic acids have been synthesized using hydrogen bonding as a mechanism for self-assembly. Phase diagrams of the binary mixtures of the hydrogen bond donor and acceptor were established using polarizing optical microscopy. The maximum isotropization point was observed for the 50 mol % composition confirming the formation of stable 1 : 1 complexes due to intermolecular hydrogen bonding. All the supramolecular assemblies built from 1 : 1 molar ratios of the hydrogen bond donor and acceptor moieties exhibit well defined smectic A (SmA) liquid crystal phases on heating and cooling cycles. The SmA phases exhibited by the complexes are not observed for the individual components. The azobenzene moiety of CPPC undergoes trans-cis-photoisomerization with a quantum yield of 0.1 and the activation energy for the thermal cis-trans-isomerization was estimated as 92 kJ mol-¹.     

Divergent Total Synthesis of Euphoranginol C,Euphoranginone D,ent-Trachyloban-3β-ol,ent-Trachyloban-3-one,Excoecarin E,and ent-16α-Hydroxy-atisane-3-one

A divergent synthetic approach to biogenetically related diterpenoids such as ent-kauranes, ent-trachylobanes, ent-beyerane, and ent-atisane has been developed. The unified synthetic route involves the De Mayo reaction to rapidly generate the bicyclo[3.2.1]-octane moiety of ent-kaurane. The key reactions also include bioinspired nucleophilic cyclopropanation generating the [3.2.1.0^2,7]-tricyclic core of ent-trachylobane and regioselective cyclopropane fragmentation furnishing ent-beyerane and ent-atisane through the nucleophilic attack and protonation of the cyclopropane ring. This strategy enables the asymmetric total syntheses of six diterpenoids from the commercially available geraniol.     

Synthesis and molecular structure study of 3-methoxy-7α-methyl-6-oxa-9β,14β-estra-1,3,5(10)-trien-17-one in solution

It was established by NMR spectroscopy that the catalytic hydrogenation of 3-methoxy-7α-methyl-6-oxa-14β-estra-1,3,5(10),8-tetraen-17-one leads to the formation of 3-methoxy-7α-methyl-6-oxa-9β,14β-estra-1,3,5(10)-trien-17-one, the structure of which was investigated in solution. The corresponding analog with a free hydroxyl group at the position 3 possesses an antiradical activity at the absence of uterotropic effect.     

Synthesis of Novel 17α-Eethynyl-5-androstene-3β, 7β, 17β-triol (HE3286)Derivatives

以脱氢表雄酮为原料,经羟基乙酰化,羰基亚乙二氧基化,CrO3/3,5-二甲基吡啶氧化,硼氢化钠还原,脱17-位亚乙二氧基,脱3-位乙酰基,用叔丁基二甲基氯硅烷(TBDMSC1)保护3,7-OH,17-位环氧化,17-位开环,脱TBDMSC1保护等十步反应合成了四个新型的17α-乙炔基-5-雄甾烯-3β,7β,17β-三醇(HE3286)衍生物,其结构经1H NMR和MS表征.     

5-雄烯-3β, 7α, 17β-三醇和5-雄烯-3β, 7β, 17β-三醇的合成

以5-雄烯二醇为原料,用微生物转化的方法合成了两个重要的神经甾体5-雄烯-3β, 7α, 17β-三醇和5-雄烯-3β, 7β, 17β-三醇。所用菌种总枝毛霉为我们自己筛选,并首次应用于5-雄烯-3β, 7α, 17β-三醇和5-雄烯-3β, 7β, 17β-三醇的合成中。     

Autooxidation of Δ17(20)-20-hydroxy derivatives of steroids. Synthesis of 3β-acetoxy-17α-hydroperoxy-16α-methylpregn-5-en-20-one and its reduction to 17α-hydroxy derivative

An efficient procedure was proposed for the synthesis of 3β-acetoxy-17α-hydroperoxy-16α-methylpregn-5-en-20-one. Optimal conditions were found for the combined process including 1,4-addition of methylmagnesium bromide at the Δ¹⁶-20-oxo fragment of dehydropregnenolone acetate and autooxidation of resulting bromomagnesium 3β-acetoxy-16α-methylpregna-5,17(20)-dien-20-olate. The subsequent reduction of the 17α-hydroperoxy group and hydrolysis of the 3β-acetoxy group afforded 17α-hydroxy-16α-methyl-substituted dehydropregnenolone acetate and its 3-hydroxy analog in high yield.     

Oxidation of Steroidal 5-En-3β-ol with Pyridinium Chlorochromate: Isolation of Key Intermediate,Steroidal 6β-Hydroxy-4-en-3-one

The PCC oxidation of 5-en-3β-ol steroids proceeds to 4-en-3,6-dione through the intermediate 5-en-3-one. The isolation of another key intermediate, steroidal 6β-hydroxy-4-en-3-one guides an understanding of the mechanism involved.     

A Facile Synthesis of 6β-Hydroxy-7α(H)-eudesma-4-en-3-one

Sesquiterpenesconstituteagroupofnaturalcompoundswhichexhibitconsiderablebiologicalactivities,suchasantiinflamatoryicytyotoxic'andcytotoxic',seedgendnation'andmolluscacidalactivities4.InrecentyearsanumberofC-6oxyfunctionalizedeudesmanesand6-dihydroagarofurans,suchascomPounds3-6',havebeenisolatedfromnaturesources.HoweverthereportSonthesynthesisofthisparticularkindofcompoundsarefewandthereportedsynthesesaregenerallybysyntheticmethodologystartingfroma-santonin2e.Ourinterestofstudyonthesynthesisof…     

Elemental fluorine: Part 22. Fluorination of 3β-acetoxy-5α-androstan-17-one using fluorine and Selectfluor

Reactions of 3β-acetoxy-5α-androstan-17-one with elemental fluorine and Selectfluor^® are reported and give contrasting results. Fluorine gives a mixture of mono-fluorinated steroids in which fluorine atoms are attached to tertiary carbon sites whereas Selectfluor^® gives fluoro-steroid systems arising from electrophilic aliphatic substitution of the most sterically accessible secondary saturated positions. The identities of the fluoro-steroid products were determined by NMR analysis and X-ray crystallography.